The present invention relates to a slot antenna, and in particular to a slot antenna having an irregular geometric shape.
There is a growing need for slot antennas for use in wireless communication devices. Referring to FIG. 1, a conventional slot antenna comprises a rectangular antenna body made from a metal foil, an elongated, narrow slot defined in the antenna body and a coaxial cable electrically connecting with the antenna body, wherein the cable has an inner core wire soldered to one side of the slot and an outer shield soldered to another side of the slot. The antenna body generally has a regular geometric shape.
However, when such a conventional slot antenna is mounted in an electronic device, the directionality of the slot antenna, and specifically the receiving angle and the gain value of the slot antenna, are affected by the geometric shape of the antenna itself and the structure of elements around the antenna in the device. Referring to FIG. 3, which shows measured radiation patterns in the X-Y plane of such a conventional slot antenna operating at three frequencies, the center line of the radiation pattern rotates around the origin an angle xcex8 from the Y-axis. Because of the altered radiation pattern, such a conventional slot antenna often cannot operate in its best mode.
Hence, an improved antenna is desired to overcome the above-mentioned shortcomings of existing antennas.
A primary object, therefore, of the present invention is to provide an improved slot antenna having an irregular geometric shape for improving the operating characteristics of the slot antenna.
A slot antenna in accordance with the present invention comprises an antenna body and a coaxial feeder cable, wherein an elongated, narrow slot is defined in the antenna body and the cable has an inner core wire soldered to one side of the slot and an outer shield soldered to another side of the slot. The antenna body is made from a metal foil, and a plurality of notches is defined in the antenna body near the slot for changing the receiving angle and improving the gain value of the slot antenna.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings.